near wellbore modeling

Near Wellbore Modeling

User Guide

2005A

Proprietary NoticeCopyright 1998-2005 Schlumberger. All rights reserved.No part of the "Near Wellbore Modeling User Guide" may be reproduced, stored in a retrieval system, or translated in any form or by anymeans, electronic or mechanical, including photocopying and recording, without the prior written permission of Schlumberger.Use of this product is governed by the License Agreement. Schlumberger makes no warranties, express, implied, or statutory, with respectto the product described herein and disclaims without limitation any warranties of merchantability or fitness for a particular purpose.

Patent informationSchlumberger ECLIPSE reservoir simulation software is protected by US Patents 6,018,497, 6,078,869 and 6,106,561, and UK PatentsGB 2,326,747 B and GB 2,336,008 B. Patents pending.

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3Contents - Near Wellbore Modeling User Guide 2005AContents - Near Wellbore Modeling User Guide 2005A.........................................................................................................3List of Figures ..... ...................................................................................................................................................................5List of Tables ...... ...................................................................................................................................................................7About this manual ...................................................................................................................................................................8

Chapter 1 - New features................................................................................................................ 112005A ................. .................................................................................................................................................................11Changes in 2004A ................................................................................................................................................................12

Chapter 2 - Introduction ................................................................................................................. 13Overview............. .................................................................................................................................................................13

Chapter 3 - Getting Started ............................................................................................................ 15Launching NWM . .................................................................................................................................................................15Getting Started with NWM ....................................................................................................................................................16

Chapter 4 - Tutorials ....................................................................................................................... 19Introduction......... .................................................................................................................................................................19Tutorial 1: Conducting a simple NWM study.........................................................................................................................23Tutorial 2: NWM Study with Cartesian LGR .........................................................................................................................35Tutorial 3: NWM Study with Unstructured LGRs ..................................................................................................................41Tutorial 4: Conducting VOI Simulations................................................................................................................................51Tutorial 5: Comparing well definitions...................................................................................................................................55Tutorial 6: Modeling existing simulation wells in NWM.........................................................................................................61Tutorial 7: Creating a new well in NWM................................................................................................................................67Tutorial 8: Modeling Flow from Production Tubing ...............................................................................................................73Tutorial 9: NWM and FrontSim Simulations..........................................................................................................................77

Chapter 5 - Reference Section....................................................................................................... 81Introduction......... .................................................................................................................................................................81ECLIPSE Office main window ..............................................................................................................................................82NWM module...... .................................................................................................................................................................83Run folder ........... ...............................................................................................................................................................1542D Well Schematic .............................................................................................................................................................1563D Viewer ........... ...............................................................................................................................................................159

Chapter 6 - Technical Notes......................................................................................................... 223Full Field Model Support.....................................................................................................................................................223VOI Validation..... ...............................................................................................................................................................224Connection Factor Calculation............................................................................................................................................225Other Resources ...............................................................................................................................................................226

Appendix A - I/O Formats............................................................................................................. 227Introduction......... ...............................................................................................................................................................227Deviation Survey Data File .................................................................................................................................................228

Appendix B - History of developments....................................................................................... 235Changes in 2003A_1 ..........................................................................................................................................................235Changes in 2003A ..............................................................................................................................................................237Changes in 2002A_1 ..........................................................................................................................................................238

4Changes in 2002A ..............................................................................................................................................................239Changes in 2001A_3 ..........................................................................................................................................................240Changes in 2001A_2 ..........................................................................................................................................................241

5List of FiguresChapter 1 - New features................................................................................................................ 11

Chapter 2 - Introduction ................................................................................................................. 13

Chapter 3 - Getting Started ............................................................................................................ 15

Chapter 4 - Tutorials ....................................................................................................................... 19Figure 4.1 Digitized VOI boundary...........................................................................................................................26Figure 4.2 Digitized Lateral in Plan View .................................................................................................................29Figure 4.3 Example of the digitized new well path. ..................................................................................................69

Chapter 5 - Reference Section....................................................................................................... 81Figure 5.1 Wells folder .............................................................................................................................................88Figure 5.2 Vertical fractured well grid, showing well control parameters ...............................................................136Figure 5.3 Horizontal fractured well, showing well controls parameters ................................................................138Figure 5.4 Well Schematic showing the well stem of Well_1.................................................................................157Figure 5.5 Well schematic showing the main stem and a lateral of Well_1. .........................................................158Figure 5.6 PostScript panel....................................................................................................................................159Figure 5.7 VRML panel ..........................................................................................................................................161Figure 5.8 Write Image panel.................................................................................................................................162Figure 5.9 Print Setup panel ..................................................................................................................................163Figure 5.10 Edit Boundaries panel...........................................................................................................................166Figure 5.11 Create Property Type panel..................................................................................................................174Figure 5.12 Property to edit or create panel ............................................................................................................175Figure 5.13 Property creation parameters section...................................................................................................175Figure 5.14 Edit scope section.................................................................................................................................176Figure 5.15 Generate by section..............................................................................................................................176Figure 5.16 Expression Builder panel ......................................................................................................................178Figure 5.17 Calculator folder....................................................................................................................................181Figure 5.18 Run Diff. folder......................................................................................................................................182Figure 5.19 Boundary interpolation folder................................................................................................................182Figure 5.20 Points Interpolation folder .....................................................................................................................183Figure 5.21 Control buttons .....................................................................................................................................183Figure 5.22 The Animate Time panel.......................................................................................................................184Figure 5.23 The timestep control buttons ................................................................................................................185Figure 5.24 The Animate Time Options panel .........................................................................................................185Figure 5.25 Object Appearance panel .....................................................................................................................185Figure 5.26 Normalization panel .............................................................................................................................186Figure 5.27 Object Rotation panel ...........................................................................................................................188Figure 5.28 Lighting panel .......................................................................................................................................189Figure 5.29 Stereo Panel .........................................................................................................................................190Figure 5.30 Property Display panel..........................................................................................................................194Figure 5.31 Cell Probe panel ...................................................................................................................................195Figure 5.32 Threshold Properties ............................................................................................................................196Figure 5.33 Integer Threshold panel ........................................................................................................................196Figure 5.34 Real Threshold panel............................................................................................................................197Figure 5.35 Control buttons .....................................................................................................................................198Figure 5.36 IJK Slicer panel .....................................................................................................................................199Figure 5.37 VOI Grid Cells panel .............................................................................................................................201Figure 5.38 VOI Domain Selection panel.................................................................................................................202Figure 5.39 Create VOI From Boundary panel ........................................................................................................202Figure 5.40 The Cell Face Selection panel ..............................................................................................................208

6Figure 5.41 Wells panel ...........................................................................................................................................210Figure 5.42 Edit Titles panel ....................................................................................................................................216Figure 5.43 Axes panel ............................................................................................................................................217

Chapter 6 - Technical Notes......................................................................................................... 223

Appendix A - I/O Formats............................................................................................................. 227Figure A.1 Meanings of the MAPAXES keyword entries........................................................................................233

Appendix B - History of developments....................................................................................... 235

-

7List of TablesChapter 1 - New features................................................................................................................ 11

Chapter 2 - Introduction ................................................................................................................. 13

Chapter 3 - Getting Started ............................................................................................................ 15

Chapter 4 - Tutorials ....................................................................................................................... 19

Chapter 5 - Reference Section....................................................................................................... 81Table 5.1 Example full field model to GeoGrid horizon mapping.............................................................................85Table 5.2 Mapping of SCHEDULE events to NWM events......................................................................................99Table 5.3 Meaning of associated bore selections..................................................................................................102Table 5.4 Supported downhole device types and panel descriptions....................................................................107Table 5.5 Operators that can be used for defining relative dates ..........................................................................121Table 5.6 Units strings that can be used to define relative dates ..........................................................................122Table 5.7 Configuration file settings ......................................................................................................................162Table 5.8 Examples of operands and property types ............................................................................................177Table 5.9 Arithmetic operators grouped by precedence, highest at top ................................................................179Table 5.10 Relative and combinatorial operators in order of precedence ...............................................................180

Chapter 6 - Technical Notes......................................................................................................... 223

Appendix A - I/O Formats............................................................................................................. 227

Appendix B - History of developments....................................................................................... 235

8About this manual

Conventions Data file, and directory names are shown in Courier, a fixed spaced font, for

clarity.

On some operating systems the file system is case sensitive for example UNIX. Be aware of this and that the files may not appear as written on your computer.

We also use the forward slash / as a directory delimiter. This is the standard for UNIX; on PCs it should be replaced by the backslash \.

The convention for batch files containing groups of operating system commands is also machine dependent. On PCs batch files will start with the character $, while UNIX we uses @.

Typefaces used All regular text is in Palatino font, and headlines at different levels are in different

levels of Helvetica Bold.

Equation variables in text are in Times Italic, for example e = mc2. This is the same font as is used in formatted equations.

Links and cross-references to other pages in this manual or others are highlighted in bright blue.

Keywords and other program code items are represented in Courier, a fixed-space font similar to that seen on DOS and UNIX screens.

Menu items are distinguished from surrounding text by being in Helvetica similar to settings often found on interactive program screens.

Program variables are in Courier like the keywords.

Standard buttons in interactive programsUnless specfically stated in the manual the listed buttons perform the following standard operations:

ApplyApplies the changes you have made in the dialog or panel. The dialog box or panel remains open.

OKApplies the changes you have made in the dialog box or panel and closes it.

CloseCloses the dialog box or panel.

9CancelCloses the dialog box or panel without applying any changes.

HelpOpens the help page for the screen, dialog box or panel.

In case of problemsShould you find an error, an omission, or something that is not clear, or you simply wish to make a comment about any part of the documentation, we will be pleased to learn about it so that we can improve our product. Please send the details in an email to:

[email protected]

giving full details, or contact your local Support Team who will be pleased to help.

New features2005A 11

Chapter 1New features

2005A

GeneralMaintenance of this application is continuing until further notice.

12 New features 2005A

Changes in 2004A

General NWM models can now be created as children of FrontSim models. An enhanced

conversion report generator is run, which is able to automatically insert SKIP keywords so that ECLIPSE NWM cases can be created and run.

Several performance bottlenecks have been identified and removed.

Well modeling A new panel to enter data for production tubing has been added. This allows you

to define the tubing simpler and faster. Also NWM now allows you to model branched tubing down hole. For further information see "Production Tubing node" on page 96.

The tabular interface used to define the down hole devices has been replaced with a new easier to use panel. Two new devices, gas lift valves and down hole pumps, have been added to extend NWM advanced well modeling.

The well editing user interface has been revamped for this release. The new multi-folder Editing panel enables you to quickly define and edit well path locations. New features include snapping to objects in the 3D Viewer and constraining the well path to simulation layers.

3D Visualization The 3D visualization now uses Open Inventor technology. This provides both

faster and smoother visualization. It is also a much more memory efficient method of visualization.

IntroductionOverview 13

Chapter 2Introduction

OverviewThe Near Wellbore Modeling (NWM) module allows you to generate a detailed local model around one or more wells in an existing full-field ECLIPSE model. The aim is to improve both the modeling of wellbore flow and its interaction with the near wellbore reservoir region.

By default, the near wellbore model inherits data from the full field model. This coarse model can be improved in a number of ways:

You can improve well definitions by using an advanced Well Editor to edit wellbore hierarchy, path, completion strategies and to set up a multi-segmented wellbore flow models.

You can model advanced well bore completions strategies using casing, production tubing in line and flow control valves.

You can import geological scale rock properties, which take precedence over properties taken from the full field model.

You can specify near wellbore reservoir fluid and rock property modifications.

You can generate local grid refinements (LGRs) automatically around wells and inserted into the full field model grid. These include both structured (Cartesian) LGRs, as traditionally used in ECLIPSE, and unstructured LGRs, which allow variable density refinements and radially symmetric grid refinements along vertical, horizontal and deviated wellbores.

Once generated, you can insert the near wellbore model back into the full field model simulation or simulate it independently. In this latter case, flux or pressure at the boundary between the near wellbore model is extracted from a full field model simulation, and used to make the full field model cells inactive when simulating the near wellbore model.

The NWM module has a dedicated graphical user interface and is highly automated. This interface includes specialized 2D and 3D along-wellbore visualization tools.

14 Introduction Overview

The NWM module is an extension option for ECLIPSE Office. ECLIPSE Office provides you with project management functionality for handling multiple simulation cases together with generic deck editing, run submission, results viewing and report generation. For an introduction to ECLIPSE Office refer to the "ECLIPSE Office User Guide".

Getting StartedLaunching NWM 15

Chapter 3Getting Started

Launching NWMTo start NWM you must first start ECLIPSE Office.

UNIX1 Type the command @office at the command prompt.

2 Select the 2005a version if prompted. Use @office -version 2005a or set the environment variable ECLVER to 2005a to avoid the prompt.

Windows 95 and Windows NT1 Start the GeoQuest Simulation Software Launcher.

2 Click on the Office button.3 Select the 2005a version and a working directory as required.

16 Getting Started Getting Started with NWM

Getting Started with NWMStarting NWM is a two-step process. First you create an ECLIPSE Office simulation case representing the full-field model, and then you create a near wellbore study case. These steps are described in the next two sections.

Creating a full field model caseTo use the NWM tool you must first open or create an ECLIPSE Office project; see the "ECLIPSE Office User Guide" for more information. The project should contain a simulation case representing the full field model on which you are going to do the near wellbore study. You can create a case representing the full field model in a number of ways:

Creating a project and case from an ECLIPSE data file Select ECLIPSE Office: File | New Project Select the ECLIPSE data file.

Hint On a PC the *.data file name extension must be selected first.

This creates a project in the same directory as the data file with the same base name but with a .off extension. If this already exists you are warned about overwriting it.

A case icon representing the model appears in the Case Manager tree.

Hint ECLIPSE Office manages a simulation keyword deck using many individual INCLUDE files. It is easier to manage these files if the project is created in a relatively uncluttered directory, and preferably one containing only the original data file.

Importing an ECLIPSE data file into a case Open an existing project. Alternatively create a new blank one by selecting,

ECLIPSE Office: File | New Project, and entering a new project filename using the file browser.

Select a case to import into by clicking on it in the Case Manager tree. A newly-created project contains a blank case that can be used.

Hint Otherwise you may want to create a new case first, using ECLIPSE Office: Case | Add Case | New

Import the ECLIPSE data file with ECLIPSE Office: Case | Import

Getting StartedGetting Started with NWM 17

Hint To create a project for an existing deck in an entirely empty directory:- launch ECLIPSE Office in the directory - create a new blank project - import the existing data file from another directory into the blank case created.

Opening an existing project containing the full field model Select ECLIPSE Office: File | Open Project, and select the project file. Select the desired full field model case by clicking on it in the Case Manager tree.

Creating a near wellbore study caseOnce a full field model has been created and selected, a near wellbore study case can be created. This can be done by clicking on the NWM button on the left-hand button bar (this is equivalent to selecting ECLIPSE Office: Module | NWM | Open NWM) and answering Yes when asked whether to create a new case.This forks a special NWM study case from the current case in the Case Manager tree and selects it. It also launches the NWM module.

Creating GRID and INIT filesThe NWM module requires that a GRID and INIT file be generated for the full field model. When an NWM study is first created, the module looks for and suggests the most likely candidates from the ECLIPSE Office project. If none are found, or if you do not want to use the files suggested, you are given the choice of browsing for the files or running ECLIPSE to generate the files automatically.

Using the ECLIPSE Office Case ManagerMultiple NWM cases can exist in an ECLIPSE Office project, together with normal cases. You can select, delete NWM cases, etc., in the same way as you can normal cases. All cases, including the NWM cases, are saved and restored with the ECLIPSE Office project. NWM cases are distinguished by the letter N in their icons in the Office Case Manager tree.When a NWM case is selected, for example after a project is opened, the NWM module comes to the front if it is already open, otherwise it may be opened by clicking on the NWM button or by selecting Module | NWM | Open NWM. The NWM module always displays the data, wells and grid for the currently selected NWM case in the ECLIPSE Office Case Manager. If a non-NWM case is selected, or the project is closed, the NWM module closes.

18 Getting Started Getting Started with NWM

TutorialsIntroduction 19

Chapter 4Tutorials

IntroductionThe tutorials are split into two logical sections. The first section presents tutorials that combine many aspects of NWM into logical work flows, such as creating wells, defining LGRs and producing multi-segmented well keywords. These are a good starting point to learn about NWM and the recommended workflow through it. The second section of tutorials are generally shorter and target specific operations that are commonly (and not so commonly) performed in NWM. If you want to find out how to accomplish something in NWM this is a good place to find out how to do it.

Work Flow TutorialsThe following tutorials are available.

"Tutorial 1: Conducting a simple NWM study" on page 23.

This tutorial demonstrates the basic steps involved in conducting a simple near wellbore model study on an existing full field simulation model. The tutorial focuses on VOI definition, well data editing, using the Multi-segment well option and results visualization.

"Tutorial 2: NWM Study with Cartesian LGR" on page 35

This tutorial extends the NWM case created in Tutorial 1. It demonstrates how to select host cells, and specify LGRs to model well completions in detail. The tutorial also deals with sampling properties from fine grids.

"Tutorial 3: NWM Study with Unstructured LGRs" on page 41

This tutorial extends the NWM case created in Tutorial 1. It demonstrates how to insert unstructured LGRs within a cartesian full field model grid. The tutorial also deals with near wellbore property editing and upscaling issues related to the use of unstructured grids. It assumes you are familiar with the construction of unstructured grids. NWM uses the same gridding tool as is used in FloGrid.

"Tutorial 4: Conducting VOI Simulations" on page 51

20 Tutorials Introduction

This tutorial demonstrates the workflow required for creating and submitting VOI-only simulation runs using the flux boundary option.

Note This tutorial requires the flux license option.

"Tutorial 5: Comparing well definitions" on page 55

This tutorial takes an existing ECLIPSE data set and shows three ways of modeling the wells in the model. It compares results obtained when simple well reconstruction is performed, complete reconstruction is performed and also show you how to model a multi completed well.

Reference TutorialsThe following tutorials are currently available.

"Tutorial 6: Modeling existing simulation wells in NWM" on page 61

The tutorial examines in detail how to create NWM well definitions from existing simulation wells. This is an extremely common operation and therefore should be well understood by users of NWM.

"Tutorial 7: Creating a new well in NWM" on page 67

In this tutorial we examine how to add new wells in a NWM case. For workflows where you want to add new wells to model predictive scenarios NWM can provide a fast interactive environment to achieve your goals.

"Tutorial 8: Modeling Flow from Production Tubing" on page 73

This tutorial discusses how to add a production tubing to an existing well and model the flow from this tubing. The merits of using the multi segment well model to model the tubing topology and properties are discussed.

"Tutorial 9: NWM and FrontSim Simulations" on page 77

In this tutorial you will learn how to create a NWM case whose parent is a FrontSim case. This is an very useful work flow for large models where it is impractical to run the FFM simulation in ECLIPSE.

How to interact with the 3D Viewer

Note For the 2004A release we switched the underlying graphics libraries to OpenInventor, giving greatly improved graphics performance. We took this opportunity to adopt the OpenInventor standard mouse interactions, giving us consistency with other OpenInventor applications such as Petrel.

The 3D Viewer has 2 distinct modes of operation: 'viewing' and 'picking'. The 3D Viewer is by default in 'view' mode (the default cursor is a hand ), which means that you can use the mouse buttons to rotate, translate and zoom the display. To pick on objects in the display you must select the 'pick' mode (the cursor changes to an arrow

). In pick mode you cannot change the orientation of the display, just pick on objects in the display.

To change mode you can either:

TutorialsIntroduction 21

use the hand and arrow button on the top left toolbar,

use the 'P' (pick) and 'V' (view) keys,

or use the key to toggle between modes.

View modeWhen in 'view' mode, interaction is as follows:

Rotate Press the left mouse button and move the mouse to rotate about the model.

Translate Press the middle mouse button and move the mouse to pan from side to side.

Zoom Press both the Ctrl key and the middle mouse button (or left and middle mouse buttons simultaneously) and move the mouse to zoom the display.

Note Note that the 3D Viewer displays a Perspective view by default.

Other buttons of interest on the left hand toolbar are:

Normalize Returns the model to the middle of the window.

Seek to Point Select this button and then click on a point on the model. The 3D Viewer zooms to the selected point. The S key provides a short cut to this button.

Perspective Toggles between Perspective and Orthogonal views of the model.

User View Returns the view to its orientation prior to a fixed view being set (with the Set View buttons below).

Set View These 6 buttons align the view with each of the primary axes.

22 Tutorials Introduction

TutorialsTutorial 1: Conducting a simple NWM study 23

Tutorial 1: Conducting a simple NWM study

IntroductionThis tutorial demonstrates the basic steps involved in conducting a simple near wellbore model study on an existing full field simulation model. The tutorial focuses on VOI definition, well data editing using the Multi-segment well option, and results visualization.

StagesThis tutorial contains the following stages:

"Before you start" on page 23

"Creating the Full Field Model Case" on page 24

"Creating a NWM Case" on page 24

"Defining Volume Of Interest (VOI)" on page 25

"Defining well paths" on page 27

"Extracting wellbore deviation from FFM" on page 27

"Importing deviation surveys" on page 27

"Defining well bore events" on page 28

"Digitizing a new lateral" on page 28

"Multi-segment well model" on page 30

"Define Segments" on page 30

"Submit Run" on page 31

"Viewing results" on page 31

"Save project" on page 32

Before you start You need the following license keys: nearwellborem, office, and gf_floviz to execute NWM. The gf_petragrid license is required to create unstructured LGRs. Though not absolutely necessary, the following ECLIPSE license options are required to simulate models generated by NWM: lgr, flux and multisegwells.

24 TutorialsTutorial 1: Conducting a simple NWM study

1 Copy all the files in the ../ecl/../2005a/nwm/tutorials/dome directory to your working directory. Check that the following files are available:

DOME.DATA, voi.bnd, nwm.grf, cart.grf, unstr.grf, p_bnd.grf, f_bnd.grf.

wells.ctl, wells.dev.

lateral.ctl, lateral.dev.

dome_g.egrid, dome_g.init.

Note The tutorial assumes you have ECLIPSE Office correctly installed and working and some knowledge of using ECLIPSE Office and FloViz.

Various ECLIPSE Office and FloViz (3D Viewer) options can be configured in a local copy of the configuration file, ECL.CFG (or ECL.CFA).

2 Make a copy of the ECL.CFG file in your working directory by running the macro @copycfg on a UNIX system or $copycfg in a command prompt window on PC.

3 Start ECLIPSE Office.

Hint If you require help see the "ECLIPSE Office User Guide".

Creating the Full Field Model Case1 Select ECLIPSE Office: File | New Project and select DOME.DATA from the browser.

This creates an ECLIPSE Office project case tree with DOME as the root case. This is the full field model.

2 If you are familiar with ECLIPSE Office review the model contents using the Data Manager.

3 Select Run to open the Run Manager and click on to submit the ECLIPSE run.

4 Wait for run to complete.

Hint The ECLIPSE Office Log Window notifies you when the run is complete.

5 Close the Run Manager.

Creating a NWM Case1 Click on the NWM button to create a new near wellbore case. 2 Answer Yes to the case creation query.3 NWM requires a GRID and an INIT file to start. By default it uses those created

during the FFM simulation. If, however, the FFM simulation has not been run (at least to initialization) then NWM prompts you to create files specifically named for the NWM case. Answer Yes to use the GRID and INIT files from the FFM simulation.


4 Name the case as nwm_lateral. This creates a child case to DOME and launches the NWM user interface consisting of the NWM Module window, the Near WellBore Viewer. The Near WellBore Viewer displays the full field model grid (notice that the button is selected).

Note Near WellBore Modeling cases have a letter N inscribed on the case folders in the ECLIPSE Office case tree.

Hint At any point, clicking on the NWM button brings the NWM Module window and Near WellBore Viewer to the foreground (or opens them if they have been closed).

5 Load the FFM simulation results using Near WellBore Viewer: File | Load Solution Data | FFM Grid and answering yes to load from DOME_E100.unrst.

The Near WellBore Viewer by default displays the OilSat property.

6 Use the animation button on Near WellBore Viewer to show changes in Oil Saturation and the final distribution at the end of simulation.

The display should show that a region of high oil saturation is present near well HORW2. This area including the injection well INJE3 is therefore a region of interest.

7 Toggle the button to turn of the cell face colors and observe the FFM well

completions.

8 Toggle the cell colors back.

Defining Volume Of Interest (VOI)Defining the volume of interest is the first step towards setting up the near wellbore model. This normally includes the well(s) of interest and provides the boundary for conducting reduced simulations using the ECLIPSE Flux boundary option.

1 Define a VOI around INJE3 and HORW2 by editing a boundary on the Near WellBore Viewer.

2 Click on Create in the VOI folder. The Near WellBore Viewer goes to top view and enters digitalization mode. The well paths are made visible.

3 Click points on the Near WellBore Viewer and digitize a polygon at least a single set of cells away from the two wells but not including any other wells.

4 Leave room around HORW2 as in Figure 4.1.

Note Use the Delete and Move buttons, to delete and move points respectively. The Backspace key deletes the last point digitized. Refer to the "FloViz User Guide" for more details on boundary editing using pick guides.

5 Click on to close the polygon and commit the edit.


6 Observe the cell coloration in the Near WellBore Viewer, which shows the VOI.By default the boundary is named VOI Boundary1.

Figure 4.1 Digitized VOI boundary

Importing a boundary.1 Select More on the VOI tab to open the Edit NWM Boundaries panel.2 Select Import and pick the file voi.bnd.

The imported boundary should appear as VOI Tutorial1.3 Select the imported boundary in the Boundary list and click +View.4 Examine the boundary in the Near WellBore Viewer. 5 Select -View and close the Edit NWM Boundaries panel.6 From the VOI Boundary list select VOI Tutorial1.

Note that the cell coloration in the Near WellBore Viewer is updated if the boundary you initially created is different from the imported boundary.

Note The default VOI is the FFM.

7 Leave the Boundary Condition as default. The simulation run is NOT a reduced run with flux, pressure or no-flow boundary conditions.


Defining well pathsWhen a VOI is defined, NWM filters the wells and categorizes them as either VOI wells or Non-VOI wells, depending on whether they are located inside or outside the VOI.

Well Tree1 Select the Wells folder to display the well tree.

The VOI wells branch is expanded by default to show the Sim Wells that are located in the VOI, HORW2 and INJE3. The tick marks next to the Sim Well nodes indicate that the wells are displayed in the Near WellBore Viewer. Uncheck the INJE3 Sim Well node and notice that the well is hidden in the Viewer, check the tick box on so the well is displayed again.NWM zooms the Near WellBore Viewer to the show only the VOI cells.

Hint The and Near WellBore Viewer toolbar buttons can be used to toggle between showing all cells or just those within the VOI.

2 Deselect the button to display the grid as lines.

This shows the wells connections at cell centers joined by gray colored lines.

Extracting wellbore deviation from FFM3 Right click on the INJE3 well tree node to open the pop-up menu. 4 Select Reconstruct | All... and create the NWM well INJE3.

A new well is added to the well tree under the Wells tree node. The well is represented by two nodes, the well node and the main stem node (the main stem node is a child node of the well node). The Near WellBore Viewer now displays the NWM well as a smooth orange line covered with a green cylinder showing the completion range. The well path color changes to red when selected.

5 Similarly, extract the well path for the well HORW2.

Hint To compare the completion range of the reconstructed NWM wells and the FFM wells switch the FFM well INJE3 well display on and compare the completions with those that have been reconstructed. You can switch the display of the NWM wells on and off using the same mechanism as with the FFM wells.

Importing deviation surveysFor best result always use the original well deviation surveys. See "Discussion" on page 32.

6 Select NWM Module: File | Import | Deviation Surveys and select wells.ctl from the browser.Optionally, open the wells.ctl and wells.dev files in text editor to analyze the data input format. For details refer to the "FloGrid User Guide".

7 Accept the default mapping suggested in the table by clicking on OK.


8 The program asks whether you wish to overwrite well paths for INJE3 and HORW2: select Continue. This imports well paths for the wells in the VOI.

9 Select Near WellBore Viewer: NWM | Clip Wells To Grid to show the full deviation surveys and click on to normalize the view.

10 Select Near WellBore Viewer: NWM | Clip Wells To Grid, and click on to normalize the display.

Defining well bore eventsImporting deviation surveys erased the perforation data that was extracted when building well paths from FFM.

1 Right click on the Sim Well INJE3 node in the well tree and select Reconstruct | Bore Events... from the pop up menu. Select INJE3 in the list of well bores and click on OK.

2 Right click on the NWM well bore node that represents the main stem of the well INJE3 and select Bore Events | Edit... This opens the Workover Events panel for the INJE3 well bore.

3 Examine the perforation that has been reconstructed from the FFM Sim Well completions by selecting the perforation event in the Existing events list. Details of the perforation are displayed in the Description text box.

4 Select Edit to display the Perforation panel. Change the Start MD to 2300 m. Click on OK to validate the data on the panel. Note the Skin Factor is set to the default value of 0.

5 Click on OK again. The perforation data is committed; the completion range along the well path is modified in the Description text on the Workover Events panel and in the Near WellBore Viewer.

6 Click on Close to close the panel.7 Similarly reconstruct the bore events for the Sim Well HORW2, and set the Start

MD to 2300 m.

Digitizing a new lateralIn order to produce the unrecovered oil near HORW2 we would like to test the option of drilling a lateral.

1 Click on and in the Near WellBore Viewer.

2 In the Near WellBore Viewer select Scene | Grid | Property... and display the SOIL property from the list of Recurrent properties. Close the Property Display panel.

3 Use the animation arrow to move the display to the last time step.

4 In the Well tree, right click on HORW2 well bore node and select Add Lateral... 5 Accept the default name Lateral_1.


6 Right-click on Lateral_1 and select Well Path | Edit... from the pop-up menu.The Near WellBore Viewer enters edit mode and relevant buttons appear at the top.

By default the Editor is in digitize mode and the view is set to Top. A Lateral_1: Edit Table window also opens providing an alternate mode of data entry and complements the mouse edits. You can type in the X, Y and Z coordinates or use cell I, J and K.

7 Digitize a branch from the main stem towards the unrecovered oil by clicking points on the plan view. Start by digitizing points in the top view starting at the branch point on the parent track as shown in Figure 4.2.

8 In the Lateral_1:Edit Table set MD = Z value column for the Reference Point and click Update View.

9 Click on to define just the areal path of the well.

The Near WellBore Viewer returns to display model and the Edit Table closes.Figure 4.2 Digitized Lateral in Plan View


Defining bore events for Lateral_1In order to reproduce subsequent sessions of this tutorial we will import an existing well path for Lateral_1.1 Right-click on well node Lateral_1, and select Well Path | Read Deviation Survey...2 Select the deviation file lateral.ctl and accept the default association

suggested in the deviation table.

3 Select Continue when prompted.4 Select Bore Events | Edit... from the pop up menu for Lateral_1. 5 Select Perforation in the Event Types drop down list and click New event.6 In the Perforation panel set the Start MD of the perforation to 2300 m and the Well

Bore Diameter to 0.625 m.7 Press the Return key or click OK, this commits the edit and closes the perforation

panel. Notice that the perforation is displayed in the Near WellBore Viewer.

8 Click Close on the Workover Events panel.

Multi-segment well modelIn order to correctly represent the flow behavior of the lateral we will use the ECLIPSE Multi-Segment Well option. We will retain the FFM grid. The use of structured and unstructured LGRs is further discussed in "Tutorial 2: NWM Study with Cartesian LGR" on page 35 and "Tutorial 3: NWM Study with Unstructured LGRs" on page 41.

Define Segments1 In the Well tree, open the pop-up menu for the HORW2 well bore and select

Segmentation | Optimal. This creates segmentation for the flow from the main stem of the well.

2 From the pop-up menu for the HORW2 well bore select Open Schematic.... The default view shows the measured depth of the well bore on the y-axis and the well bore radius on the x-axis. Notice that the perforation for this well bore is displayed as a green colored region towards the bottom of the well bore and the segmentation is drawn using a ball and arrow plot.

The top node is placed just above the connection point between the main stem of HORW2 and the lateral well, Lateral_1. Subsequent nodes are placed along the well path in cells where the well is completed.

3 Right-click on the main view window in the 2D schematic and select Display All Sections... This displays the lateral alongside the main stem of the well.

4 Close the 2D schematic.5 Right-click on the HORW2 well bore tree node and select Segmentation | Edit...

This opens the Segmentation panel, which enables you to examine the segmentation in more detail. Notice that properties such as the Diameter are read only as they are calculated using the dimensions of the well bore.


Note You can modify the segmentation using Create and Delete Segment options. Copy Properties is a useful feature to edit segment properties quickly and efficiently. The Flow Model, VFP Tables and Multiplier options open panels to edit the Multi-segment well option keywords WSEGFMOD, WSEGTABL and WSEGMULT, respectively.

6 Select Cancel on the Segmentation panel to close it.

Submit Run1 Select the Grid tab and ensure that LGR Gridding Type is set to None (Use FFM

Grid). Since the grid is unchanged there is no need to compute properties. The NWM grid uses a copy of the FFM properties.

2 Select the Run tab. 3 Leave the box for Use FFM Wells unchecked.

Notice that the Export Segmentation check box is checked. NWM detects that one or more wells flows have been segmented and therefore selects this by default.

Caution If you do not have a Multi-segment license then uncheck this box, select Export Keywords and proceed to step 6.

The default boundary condition shows that this is a NWM in-place run, that is the entire model simulated.

4 Select Export Keywords. A dialog panel opens to warn that well INJE3 is not segmented. You can choose either to segment or not segment this well.

5 Select to perform Segmentation of well INJE3.6 Select Run.

This opens the ECLIPSE Office Run Manager. 7 Check the contents of the Run Manager window. Ensure that the correct simulator

version, executable is selected and the output file type and format are correctly selected.

8 Click on to start the run.

Viewing results1 When the run is finished, NWM prompts you to load the solution data. Select Yes. 2 Close the Run Manager.3 By default the OilSat property for the NWM model is displayed in the Near

WellBore Viewer.

4 Click on to animate the saturation display.


5 Click on to display the OilSat at the end of simulation in the FFM.

6 Toggle back to the NWM model using .Notice that more oil has been drained in the NWM model.

7 Click on and select well HORW2 from the list of planes in the Plane Slicer panel selection list.

8 Uncheck Show Plane and click on Apply to remove the gray plane from the Near WellBore Viewer and show the section through the NWM grid.

9 Animate the display for OilSat and other recurrent properties.10 Select the Result button in the main ECLIPSE Office window.

This opens the Results Viewer.11 Select Results Viewer: File | Open GRF... and select the file nwm.grf.12 Review the pictures to compare the NWM and FFM results.

Save project1 In the main ECLIPSE Office window, select File | Save Project As... 2 Select OK in the warning panel and specify the name NWM_SIMPLE.

Note This project file is necessary to perform other Tutorials.

3 Select File | Exit.

Discussion1 The application stores the FFM grid and properties (initial and recurrent)

separately from the NWM grid and properties. When displaying properties ensure that the correct model is selected, or .

2 It is not a good idea to construct a VOI that intersects well paths.

3 If you plan to use unstructured LGRs to model wells within the VOI make sure you leave enough space between well paths and the VOI boundary.

4 NWM colors the cells to distinguish between VOI, non-VOI cells and LGR host cells using the NWMLGR property. The property values can be used to identify the status of a cell, that is inside/outside VOI, LGR host cell, etc.

5 Well paths are extracted from the FFM by joining the cell centres (connections defined by the COMPDAT keyword). This method is limited to simple well trajectories and may be inefficient for complex wells or grid geometry. In the extreme cases where no deviation survey is available you can edit the extracted well paths.

6 The recommended method for providing accurate well paths is to import deviation surveys from file.


7 The current Multi-Segment Well functionality in NWM only allows the setting up of simple models. Specifically, the application does the most time consuming task of setting up segments/keywords given the well paths and the NWM simulation grid. For the power user of the Multi-segment well option, the exported data can be edited in ECLIPSE Office Data Manager before run submission.

8 When Use FFM Wells option is not used (the option is unchecked) the well connection factors are computed for new wells/laterals and recomputed for other wells in the VOI. The method used by NWM is the same as that used in the Schedule program, see the "Schedule User Guide". Using the Use FFM Wells option implies that the well connections remain exactly the same as in the FFM simulation.

TutorialsTutorial 2: NWM Study with Cartesian LGR 35

Tutorial 2: NWM Study with Cartesian LGR

IntroductionThis tutorial extends the NWM case created in "Tutorial 1: Conducting a simple NWM study" on page 23. It demonstrates how to select host cells, and specify LGRs to model well completions in detail. The tutorial also deals with sampling properties from fine grids.


"Open Office Project" on page 35

"Create copy of NWM case" on page 35

"Define host cells along wells" on page 36

"Specify Refinement" on page 36

"Define properties on NWM grid" on page 37


"Discussion" on page 39

Open Office Project1 Start ECLIPSE Office in the working directory used in "Tutorial 1: Conducting a

simple NWM study" on page 23.

2 Select File | Open Project... and open the NWM_SIMPLE.OFF project created in Tutorial 1.

3 Select the nwm_lateral case and click on the NWM button.4 Select Yes to load all initial and recurrent properties.

Create copy of NWM case1 Select the Grid folder. 2 Select Cartesian LGR.

A warning panel opens. Cancel this panel.3 Return to the ECLIPSE Office window and select Module | NWM | Copy NWM

Case to create a copy of the currently selected case. 4 Name the new case as nwm_cart.

The new case is shown in the ECLIPSE Office case tree as a child case to nwm_lateral.

36 TutorialsTutorial 2: NWM Study with Cartesian LGR

5 Return to the NWM grid folder and select Cartesian LGR again and select Continue to continue with the nwm_cart as the active case.

Define host cells along wells1 Click on the Host Cells button.

This opens the NWM-Host Cells panel where you can set the host cells LGRs using various options.

2 Select the Edit using Wells radio button and click on the Edit Cell Set button. This opens the Edit Host Cells by Wells panel. By default both the wells HORW2 and INJE3 are selected.

We will build up a set of host cells by considering one well at a time.

3 Select the well INJE3 by clicking on the well name in the drop down list. 4 Let the Minimum number of horizontal and vertical cells away from perforations be

1 (default). This is the minimum host cell set to cover all the perforations in well INJE3.

5 Select Set to create the host cell set. Notice the Near WellBore Viewer has updated.

6 Now select well HORW2 on the well list. 7 Set Min. horizontal cells to 2 and set Min. vertical cells to 2. 8 Select Extend to add these cells to the host cell set created earlier for well INJE3.9 View the current host cell set (as NWMLGR property) in the Near WellBore Viewer.

It appears that the horizontal extent of the host cells for well HORW2 is larger than necessary.

10 Reduce the Min. horizontal cells value to 1.11 Select Update to modify the selection. 12 Select both INJE3 and HORW2 and select Set13 Close the Edit Host Cells by Wells and the Host Cells panels.

Specify Refinement1 Select Refinement to open the Cartesian Refinement panel.

By default only the host cells defined earlier are displayed and painted gray in the Near WellBore Viewer.

2 Select All cells in LGR radio button, and click on the host LGR around well INJE3 in the Near WellBore Viewer. This highlights only the host cells for the LGR around well INJE3. The selection is shown at the bottom of the Host Cell Selection area of the panel.

3 Enter refinements in X, Y and Z as 3 by 3 by 2. These correspond to NXFIN, NYFIN and NZFIN keywords.

4 Click on Apply.5 Select the Weights button to open the Cartesian Refinement Weights panel.

These correspond to the HXFIN, HYFIN and HZFIN keywords.


6 Enter 3 weights for X and Y each as 2, 1, 2.

7 Leave the weights for Z as default and press OK.8 Click on Generate and observe the LGR grid around well INJE3.9 In the Near WellBore Viewer, select the host cell set around the well HORW2.

All the cells that belong to different LGRs within the amalgamation around well HORW2 are highlighted.

10 Set the refinement in X, Y and Z as 2 by 2 by 2, and press Apply.11 Select All cells in K and click on the second layer of the HORW2 amalgamation. There

are 3 global layers; the middle layer should be highlighted.

12 Set the refinement in Z to 3. The refinement edit options for X and Y are read only.

13 Click on Apply.14 Click on Generate and view the LGRs.15 Click on OK to close the Cartesian Refinement panel.

Define properties on NWM grid

Sampling from the FFM grid1 Select Calculate to sample properties onto the LGRs.

2 Use and to look at how they have been inherited from the full field model grid.

Sampling from a Geological gridThe GeoGrid is a fine-scale simulation grid stored in ECLIPSE GRID and INIT file formats.

3 Select NWM Module: File | GeoGrid | Import Grid.4 Select the dome_g.egrid file from the browser, and confirm to load initial

properties and default layer mapping.

Note Please refer to "Edit Mapping" on page 84 for details on GeoGrid Horizon Mapping.

5 The Near WellBore Viewer should now display fine grid. Use and to switch back and forth between grids.

6 Click on Calculate properties again to Regen All properties by sampling from the fine grid.

7 Display PERMX.


Note Properties can also be edited using the Simulation Grid Property Editor (NWM Module: Grid | Properties | Edit Properties or Near WellBore Viewer: Edit | Grid Properties...) using simple or advanced expressions. For details please refer to "Simulation Property Editor" on page 173.

Submit Run1 Select the Run folder.2 Unchecked the Export Segmentation check box.3 Select Export Keywords and run the simulation.

This is an in-place run, that is the entire FFM with the additional NWM LGRs is simulated

Viewing results1 When the run is finished, NWM prompts you to load the simulated results. Select

Yes. 2 Close the Run Manager.

3 By default the OilSat property for the NWM model is displayed in the Near WellBore Viewer. Click on to animate the saturation display.

4 Select to display the OilSat at the end of simulation for the FFM.5 Toggle to view the NWM grid.

6 Click on and select well HORW2 from the list of wells in the Plane Slicer panel.

7 In the Plane Slicer panel uncheck the Show Plane checkbox and select Apply to remove the gray plane and show the section through the grid.

8 Animate the view. Try other recurrent properties.

9 Select the Result button in the main ECLIPSE Office window. This opens the Results Viewer.

10 Select Results Viewer: File | Open GRF..., and select the file cart.grf.11 Review the pictures to compare the NWM and FFM results.

12 Select File | Close to close the Results Viewer.

Save project1 Select ECLIPSE Office: File | Save Project.2 Select File | Exit.


Discussion1 Generating an LGR across the entire VOI is inefficient, so NWM allows you to set

a smaller host cell set within the VOI region. The most basic setting is obtained by specifying the number of cells to step in from the VOI boundary and top and bottom boundary layers.

2 NWM can quickly select host cells enclosing well completions or inside user defined boundaries and create amalgamations if necessary. Host cells created using boundaries can be added to an existing selection created using wells.

3 The NWMLGR property is used to identify host cells for different LGRs or LGR amalgamations. This property can be edited just like any other property. By displaying only specific cells in the Near WellBore Viewer and using the Property Editor to edit only Near WellBore Viewer cells very complex host cell sets can be created.

4 There are certain restrictions enforced by NWM while setting host cells based on the condition for use of LGR with ECLIPSE 100:

wells should be perforated in either local or global cells. This is not a necessary requirement for ECLIPSE 300 but should be followed for better computational efficiency.

dispersed host cells for a single well need to be amalgamated. Again this is not a requirement for ECLIPSE 300.

minimum step in of 1 cell from VOI boundary for runs with boundary conditions.

5 LGRs or LGR amalgamations are named as NWMLGR1, NWMLGR2, etc.

6 For irregular shaped host cell sets NWM sorts the cells into regular LGR sets and amalgamates them. This amalgamation is optimized so that the number of NNCs are minimum.

7 LGRs within an amalgamation are named as NWMLGR1A, NWMLGR1B and so on.

8 Refinements along I, J or K directions apply across the entire LGR or LGR amalgamation.

TutorialsTutorial 3: NWM Study with Unstructured LGRs 41

Tutorial 3: NWM Study with Unstructured LGRs

IntroductionThis tutorial extends the NWM case created in "Tutorial 1: Conducting a simple NWM study" on page 23. It demonstrates how to insert unstructured LGRs within a cartesian full field model grid. The tutorial also deals with near wellbore property editing issues related to unstructured grids.

The tutorial assumes you are familiar with the construction of unstructured grids. NWM uses the same gridding tool as used in FloGrid. For details please refer to the "FloGrid User Guide".

Note The gf_petragrid license is required to execute this tutorial.



"Create copy of NWM case" on page 42

"Generating Unstructured LGRs" on page 42

"Host Cell Selection" on page 42

"Grid to bulk only" on page 42

"Changing the bulk grid style" on page 43

"Setting the layer refinement" on page 43

"Gridding to wells" on page 43

"Property Generation" on page 44

"Well Connection Property" on page 44

"Defining Near Wellbore Properties" on page 45


"Viewing results using plane section" on page 48


Open Office Project1 Start ECLIPSE Office in the directory used for Tutorial 1.

2 Select File | Open Project...to open the NWM_SIMPLE.OFF project created in Tutorial 1.

42 TutorialsTutorial 3: NWM Study with Unstructured LGRs

Create copy of NWM case1 Select the NWM case nwm_cart and select Module | NWM | Copy NWM Case to

create a copy of the currently selected case.

2 Name the new case as nwm_unstr. The new case is shown in the ECLIPSE Office case tree as a child case to nwm_lateral.

3 Select the Grid folder and select Unstructured LGR and Continue.

Generating Unstructured LGRsUnstructured LGRs are constructed by merging domain grids for VOI wells, the VOI bulk and the VOI boundary. Arbitrary bulks and boundaries maybe created and used within the VOI. Various gridding styles for wells and bulks are available.

Host Cell SelectionThe Near WellBore Viewer updates the host cell set, which in this case is the same selection as in the NWM case nwm_cart. To ease the process of creating an unstructured grid we will change this selection to the entire VOI, see "Discussion" on page 48.

1 Select Host Cells to open the NWM - Host Cells panel.2 Check the Edit using VOI (via step in and layers) check box and select Edit Cell Set.3 Click on OK to close this panel and set the host cell selection to the entire VOI.4 Close the NWM - Host Cells panel.

Grid to bulk only1 Select Refinement to open the Grid Refinement panel.2 Uncheck the Set by absolute length box and set FFM Cell Length / I to 1.0.3 Leave the Well Refinement settings as default.4 In the Refinement Limits area set Maximum Cell Length to 60 m. 5 Click on Apply and observe that the NWM Cell Length value is updated to 53.73 m.

This gives the average size of the FFM cell.

6 Select Wells in the Object Refinement area. This opens the Near Well Gridding Controls panel.

Note that NWM has analyzed the well paths and completions and automatically selected the most appropriate grid style. Horizontal for well HORW2 and lateral and vertical for well INJE3.7 Set the Grid Style to None, and click on M-Apply.

This opens the Multiple Apply Selection panel. 8 Shift-click the last well in the list under Select Controls to highlight all wells.


9 In the Select Edits column ensure that WellGridStyle is set to None and click on OK. This applies the Grid Style to all the wells and closes the Multiple Apply Selection panel.

10 Select Close in the Near Well Gridding Controls panel. 11 Click Generate to construct the unstructured LGR.

A information panel opens when the grid is built.

12 Click OK and view the unstructured LGR.

Changing the bulk grid style13 Select Bulk to open the Edit Bulk Controls panel.14 Set the Grid Style to Hexagonal/Triangular. 15 Click Apply and Close.16 In the Grid Refinement panel, select Generate and view the resulting grid.

Setting the layer refinement17 Select Layers to open the Edit Layer Controls panel.18 Select Unit 1 (FFM simulation layer 2) from the Unit drop-down list. 19 Set Number of layers per unit to 2 and leave the Layering method as Proportional.20 Select Refine Selected Unit to open the Refine Selected Unit panel.21 Accept the default weights for the refined layers 1 to 2 as 1, 1, respectively. Click

OK to close the panel.22 Click Apply in the Edit Layer Controls panel.23 In the Grid Refinement panel, select Generate and view the resulting grid.24 Reset the number of layers to 1 for Unit 1 in the Edit Layers Control panel. 25 Select Refine Selected block units and click OK.26 Click OK in the Edit Layer Controls panel.27 Regenerate the grid.

Gridding to wells28 Select Wells to open the Near Well Gridding Controls panel.29 Select well NWMLGR HORW2 from the Well branches drop down list, and set the

Grid Style to Horizontal and click Apply.30 Similarly set the Grid Style for NWMLGR HORW2%Lateral_1 as Horizontal and

NWMLGR INJE3 as Vertical. Close the Near Well Gridding Controls panel.31 In the Grid Refinement panel select Generate.

An error with gridding the horizontal well should be reported.

32 Select Refine, to reduce the cell size, and Generate to try and rebuild the grid.

Hint You may need to repeat this process to successfully create a grid. Here by gradual refinement of the cell size we are able to accommodate the unstructured grid within the VOI and still honor the grid style and parameters.


33 Use and to show how the near wellbore grid fits into the full field model grid.

34 Select Wells again, and set the Grid Style for wells NWMLGR HORW2 and NWMLGR HORW2%Lateral_1 to Deviated (3D).

35 Set the number of Azimuthal Divisions to 6 in each case and re-grid to produce cylindrical grids around the wells.

36 Select Near WellBore Viewer: Scene | Grid | Volume of Interest | Domain Selection...

37 In the VOI Domain Selection panel select 3D_1 NWMLGR Well HORW2 as the domain and then press Apply to view the cylindrical grid around HORW2.

38 Select Near WellBore Viewer: Scene | Grid | IJK Slice and choose 3D_1 NWMLGR HORW2 as the Domain. Click Apply.

39 Use Near WellBore Viewer: Scene | Wells to toggle the well display off or reduce the well display width factor to 0.1 or less.

40 Zoom in and step through K slices to view the grid cells around the wellbore.

41 Toggle to view the grid framework. Toggle back the cell display.

42 Click default on the IJK Slice panel and close the panel.43 In the VOI Domain Selection panel select NWMLGR and click Apply to return the

display to VOI cells. Close this panel and the Wells panel.44 Click OK to close the Grid Refinement panel.

Property GenerationUnstructured grid simulations require transmissibility and cell pore volumes to be pre-computed. Therefore minimum pore volume and pinch out conditions need to known before the properties are calculated.

1 In the NWM Module, select Grid | Properties | Options... to open the Property Generation Options panel.

2 Leave the Minimum pore volume and Connect across removed cells as defaulted.3 Set the Pinch out thickness limit to 0.1 m and check the Connect across removed

cells.4 Set the Connection Porosity limit to 0.05 and Connection Permeability limit to 1

mD.

5 Click OK to close the Property Generation Options panel.6 In the Grid tab select Calculate to generate properties.

Well Connection PropertyRadial/cylindrical grids around wells can potentially create very small pore volume cells close to the wellbore and convergence problems during a full field simulation. Before proceeding with the simulation we will analyze the wellbore in greater detail.

7 Select Near WellBore Viewer: Scene | Grid | Property... and select PORV from the list of properties to display cell pore volumes.


8 Select Near WellBore Viewer: Scene | Grid | Threshold... to open the Threshold panel.

9 Double-click on the property WellConnection to move it from the All Properties list to the Active Properties list.

10 In the WellConnection(I) tab, select 2 and click on Apply. 11 Zoom in to view the cells connected to well HORW2. 12 Click on any cell and observe its pore volume in the bottom left status display bar.

The cells at the top and bottom of the well completion are extremely small (approximately 2 cubic meters). They can be easily neglected without losing the accuracy of the flow modeling into the wellbore. To see the complete statistics: Scene | Statistics

13 Similarly, select WellConnection values 3 and 1 to analyze the pore volume of the connection cells for wells Lateral_1 and INJE3, respectively.

14 View other important properties such as Trans, PermX, PermY etc., along the well.15 Click on Disable All, Apply. Close the Threshold panel.The well connection cells for Lateral_1 have extremely small cell volumes. Further analysis shows that the small cell problem is compounded by low porosity in Layer 1 where it is completed. The permeability of this layer is also much lower. One option could be not to grid this well in this simulation run.

16 Regenerate the grid after modifying the following well parameters using Refinement | Wells...

Leave the other parameters as defaulted. Click on Apply.

Leave the other parameters as defaulted. Click on Apply.

Leave the other parameters as defaulted and click on Apply. Click on OK to close the Grid Refinement panel.

Defining Near Wellbore Properties17 Select the Well tab on the NWM Module, and click on node for well HORW2.18 Select Well | Open Schematic to open the HORW2 Schematic panel.

Well HORW2

Grid Style Deviated 3D

Inner Radius 3.0 m

Cell Length 50.0m

Well INJE3

Grid Style Vertical

Inner Radius 5.0 m

Radial Divisions 2

Well Lateral_1

Grid Style None


19 Double-click on the Y-axis to open the Axis Property Editing panel. 20 Select the Range tab, and set Start of Visible Range to 2250, and press OK.21 Double click the X-axis and select Range tab. 22 Uncheck the Log box under Range Behavior to set the X-axis to linear display.

Click on OK.23 Right click on the node of well HORW2 (Well | Near Well Props) to open the

HORW2 Near Wellbore Properties panel.24 Select New to define a property modification zone and call it FLUSHZONE.25 Set up the zone geometry as follows:

26 Set up zone properties as follows:

Permeability in X, Y and Z as 300 mD, 300 mD and 50 mD, respectively.

Leave the other settings as default.

27 Click OK to insert default values.28 Click OK to accept the parameters and close the panel.

The HORW2 Well Schematic panel updates to show the radial grid cells where the property modifications are applied.

29 Close the HORW2 Well Schematic panel.30 Repeat the above steps to set up 3 zones for INJE3, name the zones A, B and C.

Zone A:

Leave the other parameters as defaulted.

Zone B:

Tubing Z Start 2600 m

Tubing R Stop 3.0 m

Color Magenta

Z start 2300 m

Z Stop 2360 m

R Stop 5 m

Color Cyan

PermX, PermY, PermZ 50 mD, 50 mD and 10 mD

Z start 2360 m

Z Stop 2410 m

R Stop 5 m

Color Magenta

PermX, PermY, PermZ 300 mD; 300 mD and 75 mD



Zone C:


31 Select NWM Module: Grid | Properties | Options...32 Set the Minimum pore volume to 5 cu. m. 33 Leave the other options as defaulted, and click OK to apply and close the panel.34 Select Calculate | Regen All in the Grid tab to apply the property modifications.35 You can view the edited property PERMX around the wellbore cells as described

in section "Well Connection Property" on page 44 or "Gridding to wells" on page 43.

Note If zones overlap then property modifications are applied in the order the zones are defined from top to bottom in the zones list.

Submit Run1 Select the Run folder, and click on Export keywords.2 In the main ECLIPSE Office window, select Data to open the Data Manager.3 Select the Schedule Section.4 Select Event | New to open the New Event panel.5 Select Simulator Controls under Event Types, and Simulator Control Parameters

(TUNING keyword) under Events, and click Apply.6 Set the following parameters:

Max Size of Next Time Step to 0.05 Max Length of Time Steps after Next to 15.0 Max Linear Iteration in a Newton to 40 (page 3 of 3).

7 Click Apply.8 Select event Simulator Tuning for High Throughput (TUNINGDP) and click Apply.

Leave all items as default and click Apply.9 Select File | Save and click OK.10 Select File | Close to close the Schedule Section. 11 Select Case Definition and switch to the Misc tab.12 Set the Stack Size of Previous Search Direction (NSTACK) to 40, and click OK.13 Select File | Close to close the Data Manager.14 In the NWM Module | Run tab select Run to open the Run Manager.

Z start 2410 m

R Stop 5 m

Color Yellow

PermX, PermY, PermZ 50 mD, 50 mD and 10 mD


15 In the Run Manager, click on to start the run.

Note The run takes a couple of minutes to complete. There could still be some convergence problems as further tuning is required but is outside the scope of this tutorial.

Viewing results using plane section1 When the run is over NWM prompts you to load recurrent properties from the

RESTART file, select Yes to load.

2 Click on the button to open the Plane Section panel and select HORW2 from the well list.

3 Uncheck Show Plane and select Apply on the Plane Slicer panel to create a section view along the well HORW2.

4 Use the animation buttons to view the change in Oil Saturation.

5 Select well INJE3 from the well list and click on Apply again. 6 In the Plane Slicer panel check the Show Plane checkbox and move the Angle of

plane extensions slider to about 50 degrees. Note that the position of the plane changes in the Near WellBore Viewer.

7 Uncheck Show Plane, check Straddle and select Apply on the Plane Slicer panel to create a section view.

8 Use the animation buttons to view the change in Oil Saturation.

9 Select the Result button in the main ECLIPSE Office window. This opens the Results Viewer.

10 Select Results Viewer: File | Open GRF... and select the file unstr.grf.11 Review the pictures to compare the NWM and FFM results.

Save project1 In the main ECLIPSE Office window select File | Save.2 Select File | Exit.

DiscussionNear wellbore property modification are applied to cylindrical zones around the well and hence are intended for use with deviated 3D or cylindrical grids.

Minimum pore volume and pinchout behavior need to specified before property generation. When gridding to wells be careful that the minimum pore volume specified does not inactivate the cells near the wellbore with connections.


Unstructured LGR grids can create convergence problems due to small cells. Some experimentation with tuning keywords is often required. Making reduced runs as described in "Tutorial 4: Conducting VOI Simulations" on page 51 can help to speed up simulations.

RestrictionsThe host cell set always includes all layers when 2.5D unstructured LGRs are used. Since aquifer cells cannot be directly connected to LGR cells this implies that bottom aquifer connections become invalid below the VOI. This is a known restriction.

LimitationsThe Gridder may sometimes fail to fit well grid domains for a particular VOI and gridding parameters, for example cell size, etc. This could be because the distance to the boundary face of the VOI is not large enough to accommodate the well domain grid. You could either enlarge the VOI or decrease the cell size. If you experience the above problem the you can try the following:

Change the Gridding Type to Single Cell for vertical wells or None for horizontal wells.

Do not grid to the offending well. Select the Advanced button in the Near Well Gridding Controls panel for this option.

Click Refine and Generate repeatedly till a grid is successfully built. This can potentially create a large number of cells.

Edit the VOI in the VOI tab and re-generate the grid.

TutorialsTutorial 4: Conducting VOI Simulations 51

Tutorial 4: Conducting VOI Simulations

IntroductionThis tutorial demonstrates the workflow required for creating and submitting VOI only simulation runs using the flux boundary option.

Note This tutorial requires a flux license.


"VOI Simulation" on page 51


"Pressure Boundary" on page 51

"Flux Boundary" on page 52

"No-flow Boundary" on page 53


VOI SimulationVOI only simulation runs can be made using pressure, flux or no-flow boundary conditions. Normally, a dumpflux run of the FFM is required to create a FLUX file, which is subsequently used in a useflux run. However, if the pressure field is known to change slowly and smoothly, the pressure at the VOI boundary can be extracted from a restart file.

Open Office Project1 Start ECLIPSE Office in the directory used for Tutorial 1.

2 Select File | Open Project...to open the NWM_SIMPLE.OFF project created in "Tutorial 1: Conducting a simple NWM study" on page 23.

3 Right mouse button click on the nwm_lateral case and select Add Clone Case. 4 Name the case nwm_lateral_press.

Pressure Boundary1 Select nwm_lateral_press and click the NWM button.2 Select Yes to load the solution/recurrent data.

52 TutorialsTutorial 4: Conducting VOI Simulations

3 Select VOI tab and check the Enable VOI-only Simulation box. 4 Select Continue on the warning panel.5 In the Boundary Condition area, select the radio button next to Pressure. 6 Select the Run tab and select dump FFM restart from the Boundary drop down

list

7 Select OK to create a FLUX file from the RESTART file.

Hint NWM prompts you if no restart solution data is available. If this occurs, select the DOME_E100.UNRST file.

8 NWM prompts with the default output FLUX file and provides an option to create a new FLUX file. Click OK to choose the default FLUX file.

9 Acknowledge the Information pop-up panel when the FLUX file has been created.

10 In the Run tab select the FLUX file just created from the Boundary drop down list.11 Select Export Keywords, and Run to open the Run Manager.12 In the ECLIPSE Office Run Manager ensure that the Input File Type and Format are

correctly selected (generally unified and unformatted) and then select .

13 When the run is complete select OK to load the restart data.14 Select ECLIPSE Office: Result | File | Open GRF... and choose p_bnd.grf. 15 Compare the in-place and VOI simulation performance of well HORW2.16 Close the Results Viewer using File | Close.

Flux BoundaryIn order to use fluxes a FFM dumpflux run is essential. The fluxes are computed with respect to the VOI created by the user. This is where the use of only FFM grid and FFM wells options is absolutely essential in order to create the FLUX file with minimum effort.

1 Select case nwm_lateral in the ECLIPSE Office case tree.2 Right mouse button click on the case and select Add Clone Case. 3 Name the case nwm_lateral_flux.

4 Select case nwm_lateral_flux.5 Select VOI tab and check the Enable VOI-only Simulation box. 6 Press Continue. 7 Click the radio button next to Flux for Boundary Condition Type.8 Select the Run tab and check the Use FFM Wells box.

Note

near wellbore modeling

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